"I don't have the luxury of looking away," said Mr. Moreno-Ocampo, who forswore intense diplomatic pressure and fears of retribution in Sudan, to charge Mr. Bashir with 10 counts of mass crimes, including three for genocide. "I have evidence."

The prosecutor's indictment argues that over a five-year period, Sudanese state military forces under Bashir's "absolute control" used a rebel insurgency as an excuse to conduct ethnic cleansing of three Darfur tribes from their native land – using tools of mass rape, murder, and deportation. Nearly 2.5 million people were displaced, and some 300,000 people, mostly civilians, died. Bashir denies any wrongdoing.

The ICC's first-ever indictment of a sitting president treads a thin line between political consequences and a slow trend toward stronger world courts, experts say.

International courts have indicted two other presidents: Slobodan Milosevic of then-Yugoslavia in 1999 and Liberian President Charles Taylor in 2003. In Sudan, the news of Moreno-Ocampo's move sparked feelings ranging from anger to defiance at the ICC, which is not recognized in Khartoum; Sudanese protested Sunday.

Yet the indictment is applauded by human rights and justice groups as overdue for Sudan, where the world has largely stood by as some 300,000 Darfurians died – and as significant in further establishing independent world justice systems.

"The indictment of Bashir and Sudan is actually a positive step in the peace process, because it will clarify the nature of the conflict," says legal expert Paul Williams of American University in Washington, who advises Darfur rebel movements on the peace process. "The court is saying one party is responsible for genocide, while the flaw in the American and European approach is to treat all sides as equal. Accommodating genocide didn't work in the Balkans and it isn't [working] in Sudan."

Yet actors as diverse as the Chinese government, former US envoy to Sudan Andrew Natsios, and authors of a new history of Darfur say the ICC is playing a dangerous game. Targeting Bashir will throw a north-south Sudan peace process into jeopardy and may give the Sudanese president an excuse to turn further wrath on the UN, aid workers, and Darfurians.

Julie Flint and Alex de Waal, authors of "Darfur: A New History of a Long War," argued in articles widely reprinted in the US and Britain, that the ICC prosecutor overstated the extent of the crimes now taking place in a recent presentation to the UN.

They warn that "Sudan's leaders believe the United Nations in Sudan is the police officer of the ICC, just waiting to enforce arrest warrants, and they have a history of responding to humiliation with rage. If the Khartoum government is indeed the beast that Ocampo depicts, is it wise to confront it in this manner...?"

In Sudan's capital of Khartoum, an aid worker who requested anonymity described fears of how the ICC charge "will impact the security situation in Darfur and in the south – whether it will lead to more fighting, closure, and harassment of camps and whether rebels will use it as an excuse to step up attacks." Aid agencies already face state persecution and staff expulsions, and several have been accused of passing information on to ICC prosecutors.

The ICC charge will undergo scrutiny by a panel of ICC judges in the coming months. If the panel issues a warrant, it is unlikely the arrest will occur while Bashir is in office.

Rise in legitimacy of justice tribunals

The ICC began to investigate Darfur in 2005 at the direction of the UN Security Council. Sudan does not recognize the jurisdiction of the ICC, and cases against such states (the US, Russia, and China also fall in that category) must proceed through the five permanent members of the Security Council.

Many legal advocates thought Bashir would be indicted last year. But Ocampo, who made his name prosecuting generals in Argentina, instead indicted two lower-level Sudanese officials first, and spent another 16 months polishing the Bashir case, sources say.

The ICC indictment puts China in an awkward postion. It relies on Sudanese oil but it also doesn't want to be portrayed as supporting a criminal as it hosts the Olympic Games in August.

Legal experts point out a slow rise in the impact of justice tribunals in just the past decade. Mr. Milosevic died in 2006 while on trial for crimes against humanity. Mr. Taylor is now on trial in The Hague for war crimes. Several fugitives charged with genocide in Rwanda have been extradited this year to the international court holding trials in Tanzania.

One reason Robert Mugabe may be clinging to power in Zimbabwe is fear of being indicted, and current policies of immunity for sitting heads of state, experts say.

Less than two decades ago, such tribunals were seen as unrealistic, impotent symbols. Some experts worry that indictments like Bashir's may be used as a substitute for diplomatic or military pressure to resolve conflicts in the region. Yet the fact that the ICC spent nearly eight years building a case – shows an independence, maturity, and persistence over the past decade.

"The Moreno indictment, if it goes ahead, is an assertion in this whole vague world system we have, that even after the 1990s, with its many liberal regimes and the creation of the ICC, that the court and justice is asserting itself as an independent force," says Ana Uzelac, an expert on human rights and the Yugoslavia tribunal at The Hague. "That's almost miraculous, and a little bit exciting."

In fact, the concerns shown by the Sudan government itself suggest how seriously the justice tribunals are taken, even if some of their most ardent advocates admit they may not deter war and violence in the short term.

"Whether the Sudan indictments are a good or a bad idea, they certainly are having a real impact," says James Hooper, director of the Public International Law and Policy Group in Washington. "The Sudanese leaders are paying attention to this ... and a key to any final deal on Darfur may be to drop the charges."

Arguing against prosecuting genocide

An outbreak of greater violence in Sudan and harm to the innocent may redound against the ICC as an argument against prosecuting genocides. Yet news reports suggest many victims and families in Darfur support a tribunal that tells them that someone interested in higher justice is watching.

"Not only do perpetrators have to look over their shoulders," says Mr. Williams. "But increasingly justice must be considered early in a conflict mediation, not just after the world powers step in. A confident ICC shows that in the long term, you can't get away from justice."

Editorial reaction in Sudan cut differently in the north and the south. Several newspapers ran angry editorials denouncing Ocampo. "Let it be known that the Sudan is supported by its people and will never bow to any threats because it fears nothing," wrote the English-language Sudan Vision. However, Alfred Taban, editor of the Khartoum Monitor newspaper, which is linked to southern rebels now part of the government, welcomed the ICC's role. "The government of Sudan always reacts to pressure and these indictments will contribute towards pressure to find peace," he said. "There will be some problems now but the International Criminal Court is acting in the interests of Sudan and the people of Darfur."